Three new vaccines have been licensed and recommended for use in adolescents. Ensuring that a high proportion of adolescents actually receive these vaccines may prove difficult, given that adolescents face many barriers to vaccination, including lack of health insurance, under-utilization of health care in general, and preventive care in particular, and missed opportunities for vaccination during health care visits. A number of strategies have been proposed to strengthen the adolescent immunization delivery system, including improving adolescent vaccination processes in primary care medical homes. Additionally, few immunization interventions have been tested in adolescent populations. In the current proposal, a study team with extensive experience in immunization delivery research will investigate the feasibility, effectiveness, sustainability, and cost of a multi-faceted adolescent immunization program to promote vaccination within the medical home. The study will be conducted in different types of primary care practices (including family medicine and pediatric practices in public, private, and managed care settings) serving adolescent patients of diverse socioeconomic and racial/ethnic backgrounds. Qualitative research, consisting of key informant interviews and focus groups, will be conducted among providers, staff, and parents to assess the feasibility and acceptability of various practice-based strategies to promote adolescent vaccination. These qualitative data will be utilized to develop a multi-faceted adolescent immunization program. We will then conduct a group-randomized trial to determine the effectiveness of this immunization program in improving adolescent immunization rates, both for newly recommended vaccines and those recommended for many years. Administrative and electronic medical record data from the group-randomized trial will also be used to determine the impact of the immunization program on the receipt of other clinical preventive services recommended for adolescents, such as health maintenance visits, height, weight, and body mass index measurement, and blood pressure screening. This investigation will also include a cost analysis, measuring the cost of the adolescent immunization program, both in terms of implementation costs and operating costs, as well as a cost-outcome analysis, measuring the cost per child vaccinated. Finally, we will conduct qualitative interviews with providers and staff after the implementation phase, to determine the factors which may facilitate or hamper sustainability of the program. Findings from this study will be directly relevant to Healthy People 2010 goals of reducing the number of indigenous vaccine-preventable diseases in the U.S. PUBLIC HEALTH RELEVANCE: While there are several important new vaccines recommended for adolescents, ensuring that adolescents actually receive these vaccines will be difficult, particularly because most adolescents are not regularly seen by their primary care provider. In this project, we will develop, implement, and evaluate an adolescent vaccination program, with the program designed to encourage adolescents to visit their usual primary care provider to receive vaccinations and other recommended preventive health services. This study will be conducted in different types of primary care settings, such as public, private, and managed care clinics serving adolescent patients of diverse backgrounds, and will provide important information to help guide future public health efforts to achieve high rates of immunization in adolescents.